Rates and Characteristics of Intermediate Mass Ratio Inspirals Detectable by Advanced LIGO
Rates and Characteristics of Intermediate Mass Ratio Inspirals Detectable by Advanced LIGO
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DOI：
10.1086/588246
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发表时间：
2007-04
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通讯作者：
I. Mandel
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作者：
I. Mandel
从中子星（NS）或恒星质量黑洞（BH）进入质量为M ~ 50-350 M☉的中质量黑洞（IMBH）的引力波（GWs）可以被计划中的先进一代地基GW干涉仪探测到。这种中等质量比吸气（IMRIs）最可能出现在球状星团中。我们分析了四种可能的IMRI形成机制：(1)通过三体相互作用使NS-IMBH或BH-IMBH双星硬化，(2)在分层三重系统中通过Kozai共振硬化，(3)直接捕获，(4)从潮汐捕获的主序星吸入CO；我们还讨论了当激励物体是NS时的潮汐效应。对于每种机制，我们预测了所产生的imri的典型偏心率。我们发现，当imri进入地面探测器的灵敏度波段时，它们将在很大程度上循环化。当GW频率达到10 Hz时，通过三体相互作用对二相进行硬化（可能是IMRI形成的主要机制）产生的偏心率在10−4以下。即使在通过直接捕获形成的偏心率最高的imri中，在GW频率达到10hz之前，大约90%的imri将循环到0.1以下。我们估计了球状星团中IMRI聚结的速率，以及由三个先进的LIGO探测器组成的网络对产生的GWs的灵敏度。我们表明，这个探测器网络每年可能会看到多达数十个imri，尽管每年一到几个的速率可能更合理。我们还估计了使用圆形IMRI模板进行数据分析所导致的信噪比损失，并发现，对于我们期望的偏心，这种损失可以忽略不计。
Gravitational waves (GWs) from the inspiral of a neutron star (NS) or stellar-mass black hole (BH) into an intermediate-mass black hole (IMBH) with mass M ∼ 50–350 M☉ may be detectable by the planned advanced generation of ground-based GW interferometers. Such intermediate mass ratio inspirals (IMRIs) are most likely to be found in globular clusters. We analyze four possible IMRI formation mechanisms: (1) hardening of an NS-IMBH or BH-IMBH binary via three-body interactions, (2) hardening via Kozai resonance in a hierarchical triple system, (3) direct capture, and (4) inspiral of a CO from a tidally captured main-sequence star; we also discuss tidal effects when the inspiraling object is an NS. For each mechanism we predict the typical eccentricities of the resulting IMRIs. We find that IMRIs will have largely circularized by the time they enter the sensitivity band of ground-based detectors. Hardening of a binary via three-body interactions, which is likely to be the dominant mechanism for IMRI formation, yields eccentricities under 10−4 when the GW frequency reaches 10 Hz. Even among IMRIs formed via direct captures, which can have the highest eccentricities, around 90% will circularize to eccentricities under 0.1 before the GW frequency reaches 10 Hz. We estimate the rate of IMRI coalescences in globular clusters and the sensitivity of a network of three Advanced LIGO detectors to the resulting GWs. We show that this detector network may see up to tens of IMRIs per year, although rates of one to a few per year may be more plausible. We also estimate the loss in signal-to-noise ratio that will result from using circular IMRI templates for data analysis and find that, for the eccentricities we expect, this loss is negligible.